Characterization of the Corrosion of Copper Materials Exposed to Anoxic Gaseous Hydrogen Sulfide Environments

ABSTRACT In this study, the corrosion behavior of electrodeposited and cold‐sprayed copper materials were systematically investigated under controlled exposure to hydrogen sulfide (H 2 S) gas in an inert atmosphere, with emphasis on the roles of surface condition, humidity, and exposure duration. In dry H 2 S, dense copper(I) sulfide films are formed with morphology largely independent of underlying copper microstructure, consistent with diffusion‐controlled growth. Pre‐oxidation delayed initial film formation, indicating slower oxide‐to‐sulfide conversion in the absence of a liquid electrolyte, though sulfide film thickness differences diminished over time. In contrast, humidity fundamentally altered corrosion behavior by introducing microscale aqueous environments via surface condensation. This led to localized corrosion features, including droplet‐induced structures and previously unreported hollow sulfide pillars governed by droplet geometry.